In the various industrial fields, as one of quality control items, it has been performed to measure weights of products and other articles; inspect whether or not the weight of each of the objects to be inspected is within a specific range; and select the objects into non-defective ones and defective ones. In the field of medicines, particularly, weight inspection has been regarded as one of extremely important inspection items. This is because a variation in weight directly leads to a variation in effective content and such a variation in effective content presents a large problem particularly for a medicament with its does required to be strictly managed.
Recently, weights of medicines such as capsules have come to be automatically inspected using a weight selecting apparatus, and as such a weight selecting apparatus there has been known an apparatus shown in FIG. 9.
The weight selecting apparatus shown in FIG. 9, adapted for weight inspection of capsules, includes a hopper “a” for continuously feeding capsules as objects to be inspected; a magazine “b” for feeding the capsules from the hopper “a” to a weighing base “g” one by one; a weighing unit “c” for measuring weights of the capsules; an acceptability determining unit (not shown) for determining the acceptability of each capsule on the basis of the measured result; and a selecting/recovering unit “d” for selecting the capsules into non-defective ones and defective ones on the basis of the acceptability determination and recovering them.
The hopper “a” is formed into an approximately funnel shape in which a specific number of capsules are to be stored. As the amount of capsules stored in the hopper “a” is reduced, new capsules are supplied from a large hopper “e” shown in FIG. 9, whereby a specific number of capsules are usually stored in the hopper “a”.
The magazine “b” is a vertically movable pipe with its upper end inserted through the hopper “a”, and a shutter “f” for opening/closing a lower end opening portion of the magazine “b” is mounted to the lower end portion of the magazine “b”. The weighing unit “c” includes a V-rail “h”, having a V-shaped cross section, for guiding each capsule supplied from the magazine “b” to a weighing base “g”; a pusher “i” for turning sideways each capsule supplied on the V-rail “h” and pushing the capsule out of the V-rail “h” to move it on the weighing base “g”; a stopper “n” for stopping each capsule moved onto the weighing base “g” at a specific position; and an injector “p” for moving each capsule from the weighing base “g” to the selecting/recovering unit. The selecting/recovering unit “d” includes an ejecting chute “j” for ejecting each capsule after weight measurement; a defective ejecting chute “k” branched from the ejecting chute “j”; and a selecting gate “m” provided at a branch point where the defective ejecting chute “k” is branched from the ejecting chute “j”.
The weight inspection using the above weight selecting apparatus is performed as follows:
That is to say, the capsules in the hopper “a” are charged in the magazine “b” in a state being aligned in a row by vertical motion of the magazine “b”, and as shown by a broken line in FIG. 9, the shutter “f” is temporarily opened when the magazine “b” reaches the lowermost point and thereby one of the capsules is discharged from the lower end opening portion of the magazine and is placed on the V-rail “h”. The pusher “i” is immediately moved in the horizontal direction to turn sideways the capsule on the V-rail “h” and move it on the weighing base “g”. The moving capsule is stopped by the stopper “n” at a specific position on the weighing base “g”, followed by weight measurement. After weight measurement, as shown by a broken line in FIG. 9, the stopper “n” is moved downward to open a charging port of the ejection chute “j” and at the same time the injector “p” is moved as shown by an arrow in FIG. 9 to charge the capsule on the weighing base “g” into the ejection chute “j” of the selecting/recovering unit “d”. At this time, the acceptance determining unit (not shown) determines, on the basis of the result of weight measurement, whether or not the weight of the capsule is within a specific range, and opens/closes the selecting gate on the basis of the determined result. In the case where the capsule is determined as a non-defective capsule having a weight being in the specific range, the selecting gate “m” closes the port of the defective ejecting chute “k”, whereby the non-defective capsule is ejected outside the apparatus through the ejecting chute “j”. On the other hand, in the case where the capsule is determined as a defective capsule having a weight being out of the specific range, as shown by a dotted line in the figure, the selecting gate “m” is opened and thereby the upper end opening portion of the defective ejecting chute “k” is opened and also the selecting gate “m” blocks the ejecting chute “j” at the branch point between the defective capsule ejecting chute “k” and the same to introduce the defective capsule into the defective ejecting chute “k”. Thus, the defective capsule is selected and recovered through the defective ejecting chute “k”. Thereafter, the above operation is continuously repeated, to thus automatically select the weights of the capsules.
The related art weight selecting apparatus, however, has a disadvantage that a so-called calibration for inspecting and confirming the accuracy of weight measurement by the weighing unit “c” must be manually performed each time, and thereby the calibration work is made burdensome.
To be more specific, the “calibration” is to compare a measuring instrument with a standard (reference) instrument or a standard sample, confirm that an error therebetween is within a reference value, and to adjust and repair the measuring instrument if the error is out of the reference value; and to stably obtain products each having a specific quality, each measuring instrument must be subjected to calibration at a necessary period determined according to the purpose and importance.
In the above-described related art weight selecting apparatus, the calibration is performed by confirming the accuracy of a balance of the weighing unit “c” using a reference weight, and adjusting and repairing the balance if an error measured is more than a reference value. However, since such an apparatus is generally configured such that a number of inspection lines composed of measurement mechanisms shown in FIG. 9 are arranged in a plurality of rows (6 rows and 12 rows types, commercially available apparatus) for processing a large amount of capsules for a short time, the calibration must be performed using the reference weight for each line, so that the calibration work takes a large labor. As a result, it is expected to develop a weight selecting apparatus capable of automatically performing the above calibration.
The above-described related art weight selecting apparatus also has a disadvantage that since capsules are carried from the hopper “a” to the weighing base “g” one by one, followed by weight measurement, and the capsules are fed to the selecting/recovering unit “d”, the carrying mechanism is complicated.
That is to say, as described above, the related art weight selecting apparatus is configured such that one capsule is discharged from the lower end of the magazine “b” and is placed on the V-rail “h” when the vertically movable magazine “b” reaches the lowermost point, and the capsule is turned sideways by the pusher “i” and at the same time it is moved to the weighing base “g” for weight measurement; and directly after weight measurement, the stopper “n” is moved to open the charging port of the ejecting chute “j” and also the capsule on the weighing base “g” is charged into the ejecting chute “g” by the injector “p”. That is to say, the carrying mechanism for carrying the capsule has a number of moving parts such as the magazine “b”, pusher “i”, stopper “n”, injector “p”, and the like, and a drive mechanism and a control mechanism for moving these parts at correct timings are required to be provided. In this way, the related art weight selecting mechanism has a very complicated mechanism for carrying capsules, which obstructs the improvement of processing ability and raises the parts cost, assembling cost and the like, and further may cause a failure in the carrying step such as breakage of capsules during carrying them.
In view of the foregoing, the present invention has been made, and a first object of the present invention is to provide a weight selecting apparatus capable of automatically performing calibration, that is, eliminating the necessity of performing the burdensome calibrating operation by manual work, thereby effectively performing high accurate, high reliable weight measurement.
A second object of the present invention is to provide a weight selecting apparatus capable of certainly carrying objects to be inspected with a relatively simple mechanism, measuring weights of the objects, and certainly ejecting the objects after weight measurement.